Many different types of root nematodes infect pines. Nematodes are microscopic worms that live in the soil. They are not related to earthworms. Root nematodes feed on plant roots, damaging and stunting them. The damaged roots can't supply sufficient water and nutrients to the aboveground parts, and the plant is stunted or slowly dies. Root nematodes prefer moist, sandy loam soils. They can move only a few inches each year on their own, but they may be carried long distances by soil, water, tools, or infested plants. Testing roots and soil is the only positive method for confirming the presence of nematodes. Contact your local County Extension Agent (see County Extension Agents) for sampling instructions and addresses of testing laboratories. Soil and root problems such as poor soil structure, drought stress, nutrient deficiency, and root rots can also produce symptoms of decline similar to those caused by nematodes. These problems should be eliminated as causes before sending soil and root samples for testing. (For information on soil problems and root rots, see Soil Structure and Water Molds.) Another type of nematode that lives inside the conducting vessels causes similar aboveground symptoms.
There are no chemicals available to homeowners to kill nematodes in planted soil. However, they can be controlled before planting by soil fumigation. (For information on fumigating soil, see Soil Fumigation and Solarization.)
Plant Care for Pinus